Gripping pliers are known from the gripping technology which have a first gripper jaw comprising a gripper jaw body and a gripper jaw element that can be moved at least in some regions relative to the gripper jaw body. Such gripping pliers generally have a second gripper jaw which has a gripper jaw body and a gripper jaw element. Such gripping pliers frequently have a sensor which is disposed on the gripper jaw body of the first gripper jaw in such a way that said sensor can be triggered by the gripper jaw element of the first gripper jaw.
Such pliers known from the prior art enable an object to be gripped to be gripped by the pliers and a sensor to be activated by means of the gripping operation. In so doing, it can be detected whether the object to be gripped has been gripped.
The present invention relates to a pair of pliers, in particular gripping pliers.
In gripping technology, it is desirable if a multiplicity of different objects to be gripped can be gripped by such pliers. These objects to be gripped relate to different workpieces, parts, articles, etc. In many applications, it is desirable that thin objects to be gripped, for example thinner than 3 mm, can also be reliably gripped and that this gripping operation can also be detected by means of a sensor. Pliers known up until now require a certain thickness of an object to be gripped in order to grip said object and for said gripping operation to be able to be detected. This limitation reduces the range of application of pliers to date.
On the basis of this definition of the problem, the aim underlying the present invention is to further develop a pair of pliers of the type mentioned above to the extent that thin objects to be gripped can also be gripped and furthermore that this gripping operation can be detected.
A pair of pliers, in particular a gripping pliers, is thus specified according to the invention, said pliers comprising a first gripper jaw. The first gripper jaw comprises a gripper jaw body and a gripper jaw element which can be moved relative to the gripper jaw body at least in some regions. The pliers furthermore have a second gripping jaw comprising a gripper jaw body and a gripper jaw element as well as a sensor. The sensor is disposed adjacent to the gripper jaw body of the first gripper jaw; thus enabling said sensor to be triggered by the gripper jaw element of the first gripper jaw. The gripper jaw element of the second gripper jaw has a contour in a region which faces the gripping region of the pliers. In addition, the gripper jaw element of the first gripper jaw has a contour in a region which likewise faces the gripping region of the pliers. Provision is hereby made for the contour of the gripper jaw element of the first gripper jaw and the contour of the gripper jaw element of the second gripper jaw to be configured, at least in some regions, in such a manner and to be disposed with respect to one another that, in the closed state of the pliers, the contour of the gripper jaw element of the first gripper jaw is in mesh at least in a partially complementary manner with the contour of the gripper jaw element of the second gripper jaw.
The solution according to the invention takes account of the fact that, in the prior art to date, only such objects to be gripped which have a certain thickness can be detected during the gripping operation. This thickness was limited in the prior art to date by the switching backlash of the sensor. For reasons of safety and manufacture, the sensor in pliers to date has a switching backlash which has, in particular, the effect that the gripper jaw element which actuates the sensor has to be spaced apart from said sensor. In the case of pliers known up until now, the gripping of an object can thus only then be detected if the thickness of said object to be gripped is greater than the width of the gap between the gripper jaw element and the sensor. In other words, the gripping of an object can only then be detected if the thickness of the object to be gripped is greater than the switching backlash of the sensor.
In the solutions according to the invention, the contours which touch each other when closing the gripping pliers are configured such that they are in mesh in a mutually complementary manner at least in some regions in order to be able to reliably grip an object to be gripped. As a result, this ensures that objects to be gripped which have an arbitrary thickness can now be gripped and detected.
In many applications, it is desirable for thin objects to be gripped, for example thinner than 3 mm or 4 mm, to be able to be gripped. In addition, the gripping of such an object to be gripped should be able to be detected. Because the solution according to the invention now enables such thin objects to be gripped to be gripped and also to be detected, the range of application of such pliers is enormously expanded. For example, plastic molded components, which have thin tabs for gripping (objects to be gripped), can be gripped on said tabs by means of the pliers according to the invention and be reliably lifted out of corresponding molds for producing plastic components. In such applications, it may be desirable that an object to be gripped has in fact been gripped (detection). Such thin tabs often have a thickness of a few millimeters or even fractions of millimeters.
It is also possible by means of the pliers according to the invention to reliably grip thin films or sheets or the like and also to reliably detect such a gripping operation.
According to one aspect of the present invention, a first sensor gap having a width B, which is determined or can be determined in advance, is formed between the gripper jaw element of the first gripper jaw and the gripper jaw body of the first gripper jaw if the pliers have not gripped anything and said pliers are furthermore in the closed state. In addition, the contour of the second gripper jaw and/or of the gripper element of the first gripper jaw is/are configured in such a manner that the contour, measured from the base of the contour to a raised portion of the contour, has a height H which is determined or can be determined in advance. Provision is made according to the invention for the height H to be greater than or equal to the width B.
The width B corresponds to the distance between the gripper jaw element and the gripper jaw body of the first gripper jaw. Said width thus corresponds substantially to the switching backlash of the sensor. By virtue of the fact that the height H of the contour is selected such that said height H is greater than the width B, it is possible for an object of arbitrary thickness to be gripped by the pliers and for this gripping operation to also be detected by the sensor despite a switching backlash of the sensor or a safety clearance of the gripper element from the gripper jaw body.
In the case of conventional gripping pliers, gripper jaws were designed symmetrically until now due to the existing manufacturing technology. This means, in particular, that the first and second gripper jaws were designed identically to date. In other words, first or upper and second or lower gripper jaws are produced in the same manufacturing process in the case of conventional gripping pliers. As a result, the contourings, for example in the form of gripping teeth, of the gripper jaws are aligned to one another in the assembled state such that the tips of the contours/gripping teeth of the gripper jaws point exactly at each other. In the case of conventional gripping pliers, this means that the gripper jaws can only be closed so far until the tips of the contouring/gripping teeth of the gripper jaws are directly on top of each other. In this state, a sensor gap or, respectively, switching backlash then remains between a gripper jaw element and a sensor. If a thin object to be gripped is now to be gripped and detected, this object to be gripped must have a thickness which is greater than the width of the sensor gap between the gripper jaw element and the sensor or, respectively, the width of the switching backlash of the sensor.
By implementing the contours in a complementary manner as described above on the one hand and by configuring a height H of the contours such that the height H is greater than or equal to the width B of the sensor gap/switching backlash on the other hand, it can be ensured in a synergistic manner that the tips of the contourings are no longer directly on top of each other when the gripping pliers are closed and thus the switching backlash of the sensor no longer limits the thickness, up to which an object to be gripped can be detected.
According to a further aspect of the present invention, the pliers further comprise an adjusting device. The adjusting device is designed in such a way that the width of the first sensor gap can be adjusted.
It is hereby ensured that the width of the first sensor gap does not have to be precisely maintained during the manufacture of the pliers because an adjustment of the width of the first sensor gap can also be carried out, for example by a user, after the manufacture of the pliers.
According to a further aspect of the present invention, the adjusting device is disposed in the region of the gripper jaw body and/or in the region of the gripper jaw element.
As a result, costly constructive changes to the pliers may not be required because the adjusting device is disposed in a simple manner in the region of the gripper jaw body and/or the region of the gripper jaw element, which regions in any case may be required in order to form the pliers.
According to a further aspect of the present invention, the adjusting device is designed as a threaded pin or grub screw.
By providing the adjusting device as a threaded pin or grub screw, a precise adjustment of the width of the first sensor gap can easily be achieved. In particular, a user without special schooling and without special tools can manipulate the adjusting device in order to adjust the width of the sensor gap.
The adjustment of the width of the first sensor gap preferably takes place after the manufacture of the pliers. In a simple manner, the adjustment can be adjusted by eye. It is, of course, also conceivable that the adjustment is automatically carried out, for example, by a measuring and/or adjusting device.
According to a further aspect of the present invention, a second sensor gap, which has a width B that is determined or can be determined in advance, is configured between the gripper jaw element and the gripper jaw body of the first gripper jaw. This sensor gap then exists between the gripper jaw element and the gripper jaw body of the first gripper jaw if the pliers have not gripped anything and are not in a closed state.
The second sensor gap is, for example, greater than the first sensor gap and thereby has the effect that the gripper jaw element of the first gripper jaw is connected to the gripper jaw body of the first gripper jaw according to a design and manufacturing tolerance range.
When closing the pliers, the second sensor gap preferably closes if the first gripper jaw is pressed against the second gripper jaw. The first sensor gap remains unaffected in this case because the first sensor gap is to prevent that a gripping operation is detected although the pliers have not gripped an object to be gripped and are only closed “empty”.
In order to ensure that the gripper jaws cannot be closed to such an extent that the gripper jaw element of the first gripper jaw is pressed against the gripper jaw body of the first gripper jaw, and the sensor gap thereby disappears if the pliers are closed and no object to be gripped has been gripped, provision is preferably made for the gripper jaws to lock before the gripper jaw element of the first gripper jaw is pressed against the gripper jaw body of the first gripper jaw. Such a locking of the gripper jaws prevents the first sensor gap from being bridged and the sensor from being triggered.
According to a further aspect of the present invention, the gripper jaw element of the first gripper jaw is pivotably connected to the gripper jaw body of the first gripper jaw, preferably via a connection region.
In so doing, the gripper jaw element can advantageously be spaced apart from the gripper jaw body and the sensor; thus enabling the gripper jaw element to be pressed in the direction of the sensor if an object to be gripped is gripped by the gripping pliers. A safety clearance or a switching backlash of the sensor can thus be maintained (first sensor gap).
According to a further aspect of the present invention, the pliers have a synchronization element. The synchronization element is designed in such a manner that the first gripper jaw and the second gripper jaw can be closed in a self-centering manner in relation to a central longitudinal axis of the pliers. The central longitudinal axis extends laterally midway between the first gripper jaw and the second gripper jaw in the gripping region of the pliers.
This results in the gripper jaws being closed in a self-centering manner when the pliers are closed, and thus a complementary mesh of the contour of the gripper jaw element of the second gripper jaw into the contour of the gripper jaw element of the first gripper jaw is implemented.
Such a synchronization element therefore enables objects to be gripped to not have to be gripped precisely centrally along the central longitudinal axis of the pliers, but said objects can also be gripped in deviation from the central longitudinal axis of the pliers. In this case, force is not exerted symmetrically on such an object to be gripped. It is nevertheless ensured that the gripper jaws are hereby not misaligned with respect to one another, whereby a complementary mesh of the contours in one another would be prevented.
According to a further aspect of the present invention, the synchronization element has a circularly cylindrical part which is disposed along a longitudinal axis parallel to the axes of rotation of the gripper jaws.
Such a circularly cylindrical part consequently enables the gripper jaws to be closed symmetrically with respect to the central longitudinal axis of the pliers. This particularly means that the contours of the pliers, i.e. the contour of the gripper jaw element of the second gripper jaw and the contour of the gripper jaw element of the first gripper jaw come into contact with each other precisely in the region of the central longitudinal axis.
The circularly cylindrical part is preferably disposed such that it perpendicularly intersects the central longitudinal axis of the pliers. As a result, a self-centering can be achieved, and a compact design of the pliers can be implemented at the same time.
According to a further aspect of the present invention, the contour of the gripper jaw element of the second gripper jaw and/or the contour of the gripper jaw element of the first gripper jaw is/are at least in some regions designed conically, tetrahedron-shaped or pyramidally.
In an advantageous manner, the contouring can be correspondingly selected such that an object to be gripped can be especially well gripped. Depending on the object to be gripped, a conical, tetrahedron-shaped or pyramidal design of the contour is particularly advantageous.
According to a further aspect of the present invention, the contour of the gripper jaw element of the second gripper jaw and/or the contour of the gripper element of the first gripper jaw is/are at least in some regions designed in an elongated fashion, in particular edge-shaped, flute-shaped, notch-shaped or groove-shaped.
The design of the contouring is advantageously adapted to the object to be gripped in order to thereby achieve an optimal adherence between the gripper jaw element of the second gripper jaw and the object to be gripped or, respectively, between the gripper jaw element of the first gripper jaw and the object to be gripped.
According to a further aspect of the present invention, the gripper jaw element of the first gripper jaw has a metallic, preferably magnetic or magnetizable region. The sensor emits a signal, preferably an electrical signal, if the metallic region of the gripper jaw element of the first gripper jaw touches the sensor or falls below a certain predetermined or predeterminable distance to the sensor.
As a result, it can be advantageously detected that an object to be gripped has been gripped if the gripper jaw element of the first gripper jaw and the gripper jaw element of the second gripper jaw touch the object to be gripped, and the gripper jaw element of the first gripper jaw is pressed towards the gripper jaw body of the first gripper jaw and thus towards the sensor by the gripper jaws being pressed together.
The metallic region is designed in this case such that said region precisely touches the sensor if the gripper jaw element touches the sensor or comes to rest on the gripper jaw body of the first gripper jaw. On the other hand, it is, of course, conceivable that the gripper jaw element has not yet come in contact with the sensor or the gripper jaw body of the first gripper jaw if the metallic region has already come into contact with the sensor. It is also conceivable that the sensor then emits a signal (detection) if the metallic region of the gripper jaw element of the first gripper jaw comes near the sensor.
The sensor is hereby preferably designed to be operated in a binary mode. This means that the sensor does not send out a signal as long as said sensor is not in contact with the metallic region, and sends out a signal if it is in contact with the metallic region. It can thus be ensured that the sensor is only then triggered if an object to be gripped has been gripped. A proximity sensor, preferably an inductive proximity sensor, is however also conceivable.
According to a further aspect of the present invention, a control unit is associated with the pliers. The control unit is designed to detect a gripping operation of the pliers if a signal is transmitted from the sensor to the control unit. To this end, the sensor is preferably connected to the control unit. The control unit is preferably designed to uniformly maintain the force which is exerted by the gripper jaws, if it has been detected that the pliers have gripped something.
As a result, it can be advantageously ensured that, for the further processing or the further operation of the pliers, it has been detected whether an object to be gripped has been gripped. In addition, it can be ensured that the object to be gripped is not damaged by the gripping pliers.